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Background This study aimed to determine the peripheral cutaneous nerve fields (CNF), their variability, and potential overlap by selectively blocking the intermediate (IFCN) and medial (MFCN) femoral cutaneous nerves and the infrapatellar branch of the saphenous nerve (IPBSN) in healthy volunteers. Methods In this prospective study, ultrasound-guided nerve blockades of the IFCN, MFCN, and IPBSN in 14 healthy volunteers were administered. High-frequency probes (15-22 MHz) and 1 ml of 1% lidocaine per nerve were used. The area of sensory loss was determined using a pinprick, and all fields were drawn on volunteers' skin. A three-dimensional (3D) scan of all lower limbs was obtained and the three CNF and their potential overlap were measured. Results The mean size of innervation areas showed a high variability of peripheral CNF, with 258.58 ± 148.26 mm2 (95% CI, 169-348.18 mm2 ) for the IFCN, 193.26 ± 72.08 mm2 (95% CI, 124.45-262.08 mm2 ) for the MFCN, and 166.78 ± 121.30 mm2 (95% CI, 94.1-239.46 mm2 ) for the IPBSN. In 11 volunteers, we could evaluate an overlap between the IFCN and MFCN (range, 4.11-139.68 ± 42.70 mm2 ), and, in 10 volunteers, between the MFCN and IPBSN (range, 11.12-224.95 ± 79.61 mm2 ). In only three volunteers was an overlap area found between the IFCN and IPBSN (range, 7.46-224.95 ± 88.88 mm2 ). The 3D-scans confirmed the high variability of the peripheral CNF. Conclusions Our study successfully determined CNF, their variability, and the overlap of the MFCN, IFCN, and IPBSN in healthy volunteers. Therefore, we encourage physicians to use selective nerve blockades to correctly determine peripheral CNF at the anteromedial lower limb.

INTRODUCTION/AIMS High-resolution ultrasound (HRUS) is the imaging method of choice to visualize peripheral nerve size, structure, and biomechanical performance. The purpose of this study was to show and quantify the effects of active and passive wrist alignment on median nerve (MN) cross-sectional area (CSA) along the forearm in a healthy population. METHODS Sixteen healthy volunteers underwent HRUS of their dominant forearm (n = 16, 10 males, 6 females, 18-55 y of age). Median nerve's CSA was assessed at four defined areas on the forearm in relation to active and passive wrist alignment. RESULTS Changes in wrist alignment were significantly associated with MN CSA (P

To (1) confirm the correct identification of the infrapatellar branches of the saphenous nerve (IPBSNs) by high-resolution ultrasound (HRUS) with ink marking and consecutive dissection in anatomic specimens; (2) evaluate the origin, course, and end-branch distribution in healthy volunteers; and (3) visualize the variable anatomic course of the IPBSN by HRUS.HRUS with high-frequency probes (15-22 MHz) was used to locate the IPBSN in 14 fresh anatomic specimens at 4 different locations. The correct identification of the IPBSN was verified by ink marking and consecutive dissection. Moreover, the IPBSNs were located in both knees of 20 healthy volunteers (n = 40). Their courses were marked on the volunteers' skin in a flexed-knee position. Distances were measured from the IPBSN branch closest to the median of the patella base (D1), center (D2), and apex (D3) and in a 45° (D4) and 0° (D5) relation to the median patella apex. Standardized photographs of all knees were mapped on 1 typically shaped knee.Dissection confirmed the correct identification of the IPBSN in 86% to 100% of branches, depending on their location. Intraindividual differences for distance measurements were observed for D1 (P.001) and D2 (P = .002). The coefficient of variation was highest for D5 (0.86) and lowest for D1 (0.14). Mapping of the nerve branches on a typical knee showed a highly variable course for the IPBSN.This study confirmed the reliable ability to visualize the IPBSN and its variations with HRUS in anatomic specimens and in healthy volunteers; such visualization may therefore enhance the diagnostic and therapeutic management of patients with anteromedial knee pain.Ultrasound successfully pinpoints the variable course of the IPBSN from the origin to the most distal point and, therefore, may enable the correct identification of (iatrogenic) nerve damage in every location.

Introduction: The value of imaging the deep branch of the ulnar nerve (DBUN) over its entire course has not been clarified. Therefore, this study evaluates the feasibility of visualizing the DBUN from its origin to the most distal point. Methods: We performed high-resolution ultrasound (HRUS) with high-frequency probes (18–22 MHZ), HRUS-guided ink marking, and consecutive dissection in 8 fresh cadaver hands. In both hands of 10 healthy volunteers (n = 20), the cross-sectional area (CSA) was measured at 2 different locations (R1 and R2). Results: The DBUN was clearly visible in all anatomical specimens and in healthy volunteers. Dissection confirmed HRUS findings in all anatomical specimens. The mean CSA was 1.8 ± 0.5 mm2 at R1 and 1.6 ± 0.4 mm2 at R2. Discussion: This study confirms that the DBUN can be reliably visualized over its entire course with HRUS in anatomical specimens and in healthy volunteers. Muscle Nerve 56: 1101–1107, 2017

Purpose The purpose of this study was to assess the diagnostic accuracy of T1-weighted and T2-weighted contrasts generated by the MR data postprocessing software SyMRI (Synthetic MR AB, Linköping, Sweden) for neonatal brain imaging. Methods In this study 36 cases of neonatal MRI were retrospectively collected, which included T1-weighted and T2-weighted sequences as well as multi-dynamic multi-echo (MDME) sequences. Of the 36 neonates 32 were included in this study and 4 neuroradiologists independently assessed neonatal brain examinations on the basis of conventional and SyMRI-generated T1-weighted and T2-weighted contrasts, in order to determine the presence or absence of lesions. The sensitivity and specificity of both methods were calculated and compared. Results Compared to conventionally acquired T1 and T2-weighted images, SyMRI-generated contrasts showed a lower sensitivity but a higher specificity (SyMRI sensitivity 0.88, confidence interval (CI): 0.72–0.95; specificity 1, CI: 0.89–1/conventional MRI: sensitivity: 0.94, CI: 0.80–0.98; specificity: 0.94, CI: 0.80–0.98). Conclusion The T1-weighted and T2-weighted images generated by SyMRI showed a diagnostic accuracy comparable to that of conventionally acquired contrasts. In addition to semiquantitative imaging data, SyMRI provides diagnostic images and leads to a more efficient use of available imaging time in neonatal brain MRI.

Purpose To evaluate in a prospective study the possibility of visualization and diagnostic assessment of the recurrent motor branch (RMB) of the median nerve with high-resolution ultrasound (HRUS). Materials and methods HRUS with high-frequency probes (18–22 MhZ) was used to locate the RMB in eight fresh cadaveric hands. To verify correct identification, ink-marking and consecutive dissection were performed. Measurement of the RMB maximum transverse-diameter, an evaluation of the origin from the median nerve and its course in relation to the transverse carpal ligament, was performed in both hands of ten healthy volunteers (n = 20). Cases referred for HRUS examinations for suspected RMB lesions were also assessed. Results The RMB was clearly visible in all anatomical specimens and all volunteers. Dissection confirmed HRUS findings in all anatomical specimens. Mean RMB diameter in volunteers was 0.7 mm ± 0.1 (range, 0.6–1). The RMB originated from the radial aspect in 11 (55%), central aspect in eight (40%) and ulnar aspect in one (5%) hand. Nineteen (95%) extraligamentous courses and one (5%) subligamentous course were detected. Three patients with visible RMB abnormalities on HRUS were identified. Conclusion HRUS is able to reliably visualize the RMB, its variations and pathologies. Key Points • Ultrasound allows visualization of the recurrent motor branch of the median nerve. • Ultrasound may help clinicians to assess patients with recurrent motor branch pathologies. • Patient management may become more appropriate and targeted therapy could be improved. Electronic supplementary material The online version of this article (doi:10.1007/s00330-016-4671-1) contains supplementary material, which is available to authorized users.

Introduction: Neuralgic amyotrophy (NA) often imposes diagnostic problems. Recently, MRI and high-resolution ultrasound (HRUS) have proven useful in diagnosing peripheral nerve disorders. Methods: We performed a chart and imaging review of patients who were examined using neuroimaging and who were referred because of clinically diagnosed NA between March 1, 2014 and May 1, 2015. Results: Six patients were included. All underwent HRUS, and 5 underwent MRI. Time from onset to evaluation ranged from 2 weeks to 6 months. HRUS showed segmental swelling of all clinically affected nerves/trunks. Atrophy of muscles was detected in those assessed >1 month after onset. MRI showed T2-weighted hyperintensity in all clinically affected nerves, except for the long thoracic nerve, and denervation edema of muscles. Conclusions: HRUS and MRI are valuable diagnostic tools in NA. This could change the diagnostic approach from one now focused on excluding other disorders to confirming NA through imaging markers. Muscle Nerve 54: 1079–1085, 2016

The aim of this study was to evaluate the possibility of visualizing Pacinian corpuscles in the palm of the hand with high-resolution ultrasound (HRUS). In this prospective study, HRUS with a high-frequency probe (22 MHz) was used. The palms of two fresh cadaveric hands were screened for potential Pacinian corpuscles. Still ultrasound images and dynamic video sequences were obtained. In five regions with large amounts of suspected Pacinian corpuscles, tissue blocks were excised and histologically processed, and corresponding slices were compared with ultrasound images. Further, the transverse diameters of five Pacinian corpuscles, at the level of the metacarpal heads in the palm, were assessed on both sides (in total 100) in healthy volunteers. On ultrasound, Pacinian corpuscles presented as echolucent dots in the subcutis, adjacent to digital nerves and vessels and located 2-3 mm beneath the surface. On histologic sections, these echolucent dots corresponded to Pacinian corpuscles with respect to their position and topographic relationships. The mean transverse diameter for all volunteers was 1.40 ± 0.23 mm (range: 0.8-2.2 mm). This study confirms the ability to reliably visualize Pacinian corpuscles with HRUS, which contributes to our basic understanding of ultrasonographically visible subcutaneous structures and may enhance the diagnosis of pathologies related to Pacinian corpuscles.

The value of imaging the deep branch of the ulnar nerve (DBUN) over its entire course has not been clarified. Therefore, this study evaluates the feasibility of visualizing the DBUN from its origin to the most distal point.We performed high-resolution ultrasound (HRUS) with high-frequency probes (18-22 MHZ), HRUS-guided ink marking, and consecutive dissection in 8 fresh cadaver hands. In both hands of 10 healthy volunteers (n = 20), the cross-sectional area (CSA) was measured at 2 different locations (R1 and R2).The DBUN was clearly visible in all anatomical specimens and in healthy volunteers. Dissection confirmed HRUS findings in all anatomical specimens. The mean CSA was 1.8 ± 0.5 mmThis study confirms that the DBUN can be reliably visualized over its entire course with HRUS in anatomical specimens and in healthy volunteers. Muscle Nerve 56: 1101-1107, 2017.

Neuralgic amyotrophy (NA) often imposes diagnostic problems. Recently, MRI and high-resolution ultrasound (HRUS) have proven useful in diagnosing peripheral nerve disorders.We performed a chart and imaging review of patients who were examined using neuroimaging and who were referred because of clinically diagnosed NA between March 1, 2014 and May 1, 2015.Six patients were included. All underwent HRUS, and 5 underwent MRI. Time from onset to evaluation ranged from 2 weeks to 6 months. HRUS showed segmental swelling of all clinically affected nerves/trunks. Atrophy of muscles was detected in those assessed1 month after onset. MRI showed T2-weighted hyperintensity in all clinically affected nerves, except for the long thoracic nerve, and denervation edema of muscles.HRUS and MRI are valuable diagnostic tools in NA. This could change the diagnostic approach from one now focused on excluding other disorders to confirming NA through imaging markers. Muscle Nerve 54: 1079-1085, 2016.

This study evaluated the potential of three-tesla diffusion tensor imaging (DTI) and tractography to detect changes of the radial (RN) and median (MN) nerves during transient upper arm compression by a silicon ring tourniquet.Axial T2-weighted and DTI sequences (b = 700 s/mm(2), 16 gradient encoding directions) of 13 healthy volunteers were obtained. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of the MN and RN were measured at the spiral groove and further visualized in 3D by deterministic tractography (thresholds: FA = .15, angle change = 27°).Local/lesional RN FA values increased (p = 0.001) and ADC values decreased (p = 0.02) during a 20-min upper arm compression, whereas no significant FA (p = 0.49) or ADC (p = 0.73) changes of the MN were detected. There were no T2-w nerve signal changes or alterations of nerve trajectories in 3D.Acute nerve compression of the RN leads to changes of its three-tesla DTI metrics. Peripheral nerve DTI provides non-invasive insights into the "selective" vulnerability of the RN at the spiral groove.• DTI-based neurography detects nerve changes during acute nerve compression. • Compression leads to a transient increase in local radial nerve FA values. • DTI provides insights into radial nerve vulnerability at the spiral groove.